Continue refactoring shaders

shader/ellipse.geom

@@ -2,7 +2,8 @@
 layout (triangles) in;
 layout (triangle_strip, max_vertices = 4) out;
 in vec4 vCol[];
-out vec4 gColor;
+out vec4 gColorC;
+out vec4 gColorE;
 out vec2 gBoundingBox;
 
 uniform vec2 winSize;
@@ -13,7 +14,8 @@ void main()
   vec3 pa = gl_in[0].gl_Position.xyz;
   vec3 pb = gl_in[1].gl_Position.xyz;
   vec3 pc = gl_in[2].gl_Position.xyz;
-  gColor = vCol[0];
+  gColorC = vCol[0];
+  gColorE = vCol[1];
 
   gBoundingBox = vec2 (-1,1);
   gl_Position = vec4 (pb, 1);